Process of making asphalt.



R. C. DUNDAQ.

PROCESS OF MAKING ASPHALT.

APPLIUATION FILED numel 1910.

1,056,980. l Patented Mar.25,1913.

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PROCESS OF MAKING ASPHALT. APPLIOATION FILED JAN.26, 1910 1,056,980, Patented Manz, 1913.

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UNITED STATES PATENT OFFICE.

ROY C. DUNDAS, 0F LOS ANGELES, CALIFORNIA, ASSIG-NOR T0 DUNDAS ENGINEERING COMPANY, A CORPURATION 0F CALIFORNIA` PROCESS 0F MAKING ASPHALT.

Specication of Letters Patent.

Patented Mar. 25, 1913.

Application 1ed`January 26, 1910. Serial No. 540,183.

nal asphalt base of the crude petroleum by so distillingl the natural oil that no. new compounds of the hydrocarbon group are formed.

Briefly stated, the methods heretofore employed for the treatment of hydrocarbon oils having an asphalt basehave had,in view` principally the obtainment Vof the by-prodaguets contained therein, the preservation of the base "or the basic element in the oil being merely incidentalto the refining process.

Th'e crude oil is let into cylindrical stills and there subjected to high heat which is convectivly diffused throughout the body. On account of the density and viscosity of the crude petroleum, the convection of heat is slow, and on account of the low conductivity of the heavy hydrocarbon, the heat distribution is by no means uniform, the lower strata becoming heated to an excessive degrec, while the upper strata are compara-v tively unai'ected. The result of the high heat employed and the uneven distribution of heatis eventually a cracking of the basic product, causing some of the vital hydrocarbon globules contained in the pure asphaltic base to be entrained or carried over with the distillates, and so'me to be separated from the mass; these globules, uniting with the products of distillation in suspension fall back into. the distilling petroleum and recombine with the molecules.

The meta-morphism thus resulting vitiates the balance of the crude petroleum in the still, and deteriorates by such chemical reaction the resultant base.

The principal objects of the invention therefore, are to expedite the fractionation vof. the crude oilfwithout destructively distilling the mother product, to rid the viscous mass of oil of the nascent gases liberatedduring the process of heating, to preserve intact the basic product, and finally to produce an asphalt having great duct-ility and fibrous tenaclty.

- The accompanying drawings illustratetoneform of apparatus employed 'for carrying out the process.

E igure l, is an end elevation, partly in section showing the interior of the still, the

' circulating pump and a sectional elevation of the distilling vatin which the linal distillat-ion occurs wit-hout further heat. Fig. y2, is a side elevation of the same .partly broken showing the condensing pipes, the

`baille boxes and the direction of travely of the radiated heat. Fig.v 3, is a side lelevation of the furnace showing themanifolds, heating chamber, and blower for forcing air through the manifolds. Fig. 4, is an end elevation partly broken, and Fig. 5, is a vfragmentary view of the still, and conenser showing the vapor pipes connected with the still.

The still shown in the drawings, consists of a casing, 1, provided with a series of baille boxes 2, superposed and arranged in zig-zag fashion, for the purpose of causing the heat to circulate about all portions of the same. The crude petroleum is let into the said battle boxes through the pipes 3, connected with the supply, .which pipes are arranged to feed the oil at that point of the baliiev boxes which is hot-test. The oil from the pipes 3, Hows into troughs 4, located in the ends ofthe boxes 2, and overowing, travels 'by gravity over the inclinedbottoms of the baiiie boxes 2. Duringits travel the oil is agitated or more accurately speaking turned over, by means of the ritiies 5, disposed transversely in said boxes, whereby the greater percentage of the lighter products are freed, the heat in the upper box A being sutiicient only to initially distil or drive off the lighter vapors, which escape through the pipes 6, into the manifold B and from there to the condenser. .From the baffle box A, the oil discharges through the loutlet 7 which is connected with a goose-neck joint 8, swiveled thereto, by means of which the depth of the oil in the bottom of the baliie boxes is gaged.v This arrangement is desirable for increasing or reducing the speed of fractionation of the oil, Lthe amount of the distillatesgiven olf being visible in the tail boxes L. From the balile box A, the oil Hows through the pipe 9|, into the trough 4, of the battle box and is distributed in a thinv layer or in thin sheetsA by means of a pump 10, and forced up' ivardly through a pipe 11,"located centrally of the tank 12, strikin eventually against a concave plate l13, whic deiects the oil-base downwardly into the circular troughs or trays 14, from which it falls in turn to the bottom of the tank. These troughs or trays 14 are mounted on brackets m which in turn are fastened to the stand pipe- 11:; Disposed above said troughs or trays are a plurality of circular funnels n of considerably largerdiameter than the troughs or trays 14, the bottoms of said funnels being perforated, as seen at 0. Such tunnels n are connected with said stand pipe by a bracket p. In the drawing, the approximate depth of the residual product is shown on a level with, the pipe 15, which is connectedVwit-h the pump, and which continuously circulates the asphalt until the vapors otherwise impossible of liberation are extracted by the vacuum pipe 16 connected with the tank. The final product is drawn from the tank 12, by the drawsoif pipe 17, connected with the 'bottom thereof,

Crude petroleum having an asphalt hase" should be distilled with a' uniform heat, that.

is to say, uctationsshould be avoided, and in order to furnish a large volume of heat at determined temperature, I have devised an apparatus for furnishing radiated heat. This apparatus is shown in Figs. 3, 4 and 5', and consists of a blower A, which furnishesair through pipe A toan inlet manifold B', within the furnace C, and having a number of branch pipes D. which connect with anA outlet manifold E. The air is heated by the combustion of fpel at F, in the furnace, the quantity .of ai being controlled by the blower, and the Itemperature by the oil burner F'. G designates the outlet for the gases from the combustion chamber F, and furnace C; Said manifold E. connects with the still at H, the heat traveling through the still exhausting at H. Vapor Hows from ipes 6 into the manifold B connects with t e condenser K, provided with a tail boxl L, through which the condensed vapors flow. A-vac'uum pi e M, is provided'on the tail box L, and this vacuum pipe. communicates with a vacuum receiver, not shown, for the purpose of carrying a low pressure on the still.

During the treatment of the oil in the still the inspissation of the crude oil is gradual, the lviscosity being increased as the volatilization'proceeds. A tthe bottomA 'nal in the still.

of t-he still the heat is greatest, but at no time must the heat exceed atemperature which will destructively distil the crude petroleum or crack the basic product. vhile not `specifically stating what such tempera' ture is, it is believed that between 575% and 600% F. depolymerization begms, and to prevent such destructive action. radiated heat alone is used, which is easilyiregulated,

and more evenly distributed over the area than direct flame, at the same time causing a more speedy and certain liberation of the lighter products.

The total abstraction of all of the vapors from the crude petroleum is by no means rl`he homogenous inspissated body still contains very volatile vapors -when discharged from the last battle bo-x of the still. What may be called atomic lvaporsil have found to be prevalent in a refined body of petroleum, from which supposedly all ofthe condensable gases have been driven. My experiments have led to the assumption, that molecular gaseous impregnation exists and that ordinary refining though coupled with accelerating means. cannot avail to produce heterogeneity of the mass suiiicient to expose each molecule to the heat. 'A disintegration. without destructive distillation. permits of a thorough convection, consequently dissipating -cone verted gases. I have therefore devised a means, shown in Fig. 1, and complementary to the still, for ridding the asphaltic product of those vapors which, though generated during treatment in the still. cannot escape onaccount ofthe viscous nature of the reslduum. Thls means conslsts, as above explained, of a plurality of superposed trays. over the edges of which, the asphalt flows in attenuated streams, causing therebyv the excessively light vapors to be drawn off by the vacuum created in the v-at.

At present, in cylinder distilling, air and steam in jets, are used to force the vapors through the mass. During` this process of forcing, the purity of the vapors is vitiated by the entrainment of hydrocarbon solids,

which are forcibly segregated from the base, hencerequiring subsequent acidular treatment for purification. Artificial penetrative agitation, while more speedily liberating the distilled products, disrupts, without homogeneous disintegration of the globular constituents, the base of the natural petroleum, and in this manner allows a large per centage of the petrolene particles to be carried over with the subtilized products. But

some of these in sus ension with the va orized products, comblne with them, and attaining by such combination, a higher atomic'Y weight, return to the bulk, recombining with the base, produce under excessive heat metamorphism, both chemically and mechanically. When the heat under the still vacillates, some of. the vapors which are carriedoif, with the assistance of air or steam,.condense before leaving the still and return to the bulk. This is commonlyV known as cracking of the oils. The result system of cylinder distilling.; The natural oil flowing in thin layers or sheets absorbs heat in a uniform degree liberating the gases, as they are generated, and permitting of'their unimpeded escape without having to pass through a bulky quantity, which necessarily restrains their escape. Since, however, the object of this invention production ofa `perfect asphalt, which embodies the essentials of ductility, tenacity and resistance to heat, the preservation of the purity of the lighter products is a prima] requisite, and these must not be contaminated by hydrocarbon solids. Where, therefore, under this system, the distillation has progressed systematically and the products respond to the test of chemical purity, it is obvious thatthel base of the natural oil also remains in acondition of purity,

being vfree from the Achemical reformations-- resulting from forced fractionation. In order therefore. to produce an asphalt of strong ductility and not susceptible to changes in .temperature within determined limits, the oil is caused to flow gradually by gravity to meet in its progression a higher degree of heat, a temperature varying from a determined minimum to va determined maximum being at all times maintained in order to cause a gradual conversion of the basic constituents in the petroleum into an asphalt `of proper tenacity and consistency.

If the heating of the crude petroleum exceeds a "determined limit, the petrolene is changed to asphaltene, and an asphalt in which the -petrolene has undergone such a change, 1s lacking necessarily in the qualities which give to it ductility and proper fibrous elasticity. Under existing processes -no asphalt can be produced under 600% F. nor would it be possible because 'of the bulk inhibiting thermal penetration. A

is the continuous `production of asphalt from l which the chemical constituents have been freed is ylikewiseimpossible, because the chemical composition of natural petroleum is changedby present methods, petrolene, the essential ingredient 'having suffered 60 molecular disruption or at least a chemical metamorphosis vof lits component element-s;

gases statu nascendz', but incapable of escape, inhere in all `of the present asphalts when discharged from the still, and these gases recondense upon cooling and re-unite by atomic affinity withy the base.v The result isa product perhaps properly incrassated, .but lacking in tenacious ductility and malleability, and a loss of those already gen 70 eratedA gases.

In the specification I have employed the term destructive distillation, and desire to have it understood that by such term I mean such distillation ofthe petroleum that,

will cause ca-rbonization or coking of the base. vWhat Ifclaim, is

l. The method of making asphalt from crude petroleum which consists in causing the natural oil to low continuously in undulatory strata, heating the strata so that the temperature on the same varies from a determined minimum to a determined maximum, whereby to'drive oif the lighter prod- 85 `ucts and gradually inspissate the base, and

finally causing the inspissated product to fall in attenuated streams n vacuo to liberate the nascent vapors therefrom.

2. The methodof making asphalt from crude petroleum which yconsists in causing the natural oil to flow by gravity in -continuous u'dulatory strata n vacuo, then varyingly heating -the strata from a determined minimumto a determined maxiai mum whereby to gradually and evenly drive olf the -by-products and inspissate the base. and finally causing t-he resultant product to lcontinuously fall in attenuated stre-amse I whereby to liberate all yor nearly all of the nascent vapors until the desired grade is obtained. A

In testimony whereof'V I aiix my signature lin the presence of two witnesses.

ROY C..DUNDAS. Witnesses:

H. M. BARsToW, EDGAR LEAVITT. 

